Answer:
$.50 per attendee
Explanation:
The rate of change for a line is equal to the slope
To find the slope we use two points (10,10)and (70,40)
m = (y2-y1)/(x2-x1)
(40-10)/(70-10)
30/60
1/2
Since this is money, we change to decimal form
$.50 per attendee